Anchoring system between a concrete component and a steel component

ABSTRACT

An anchoring system for forming a non-releasable connection between a concrete component, has a reinforcement containing at least one steel bar mesh, and a steel component. At least one anchoring element formed of an anchor strip is cast into the concrete component in such a way that at least one connecting surface projects at least partially from the concrete component. This improves the loadability of the anchoring. For this purpose, the anchor strip has a number of recesses which extend at least partially into the concrete component and which are each traversed by at least one steel bar of the steel bar mesh.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation application, under 35 U.S.C. §120, of copendinginternational application No. PCT/EP2012/059349, filed May 21, 2012,which designated the United States; this application also claims thepriority, under 35 U.S.C. §119, of German patent application No. DE 102011 105 329.1, filed Jun. 3, 2011; the prior applications are herewithincorporated by reference in their entireties.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to an anchoring system for forming a nonreleasable connection between a concrete component and a steelcomponent. It also relates to a reinforced concrete-steel structureproduced therewith.

The material concrete, and in particular the variant reinforcedconcrete, can be widely used as a building material. However, in manycases, the building material is not used exclusively, but in combinationwith other building materials. Here, it is usual for individual elementsor entire assemblies to be produced from concrete or reinforced concreteand for supplementary elements or assemblies to be produced from anothermaterial, for instance steel. The individual elements or assemblies mustbe connected to one another during assembly. In this case, anchoragesare frequently used.

The prior art discloses corresponding anchorages or anchoring systems indiverse variations. The configuration of such anchorages or anchoringsystems substantially depends on which materials are to be combined withone another and to which loading an anchorage or an anchoring systemwill be exposed.

Austrian patent application AT 505 269 A1, corresponding to U.S. Pat.No. 7,617,990, discloses an anchoring system which has been configuredespecially for anchoring a concrete component on a steel support, thatis to say a steel component. According to the application, astrip-shaped body made of steel serves as an anchoring element and hasfor that purpose at least one recess. The anchoring element projectswith the recess into the concrete component, and it is welded to thesteel support on that side of the anchoring element which is oppositethe recess. However, the permissible maximum loading of such ananchorage is not sufficient for diverse applications.

SUMMARY OF THE INVENTION

The object on which the invention is based is therefore to develop ananchoring system which is further improved and moreover can be subjectedto greater loading, in particular for connecting a concrete component toa steel component.

With the foregoing and other objects in view there is provided, inaccordance with the invention a reinforced concrete-steel structure. Thereinforced concrete-steel structure includes a concrete component, areinforcement having at least one steel bar mesh with steel bars, asteel component connected non-releasable to the concrete component, andat least one anchor strip having a connecting surface for connecting tothe steel component and defining a connection between the steelcomponent and the concrete component. The anchor strip is cast into theconcrete component such that the connecting surface of the anchor stripprojects from the concrete component. The anchor strip has a number ofrecesses formed therein and extend at least partially into the concretecomponent and each is traversed by at least one of the steel bars of thesteel bar mesh. Each of the recesses is an indentation open toward thesteel component and separating the connecting surface of the anchorstrip into subregions spatially separated from one another.

An anchoring system corresponding to the teaching of this inventionserves for forming a nonreleasable connection between a concretecomponent and a steel component. For this purpose, at least one anchorelement formed of an anchor strip is cast into the concrete component insuch a way that it projects at least partially from the concretecomponent. The exposed segment acts as connecting surface to the steelcomponent and is fixedly connected thereto. A number of recesses areprovided on the anchor strip on the connecting surface side and extendinto the concrete component. Incorporated into that concrete componentis at least one steel bar mesh as a reinforcement, wherein each recesson the anchor strip is traversed by at least one steel bar of the mesh.In this way, forces which act on the steel component are transmitted viathe anchor element to the reinforcement of the concrete component. Theacting forces thus act less locally and can accordingly be betterabsorbed by the concrete component. Consequently, the anchoringcapacity, in particular with respect to tensile loading, issignificantly increased by comparison with other anchoring systems.

According to a preferred embodiment, each recess separates theconnecting surface into at least two sub regions which are spatiallyseparated from one another. Thus, during the manufacture of the anchorstrip, each recess is incorporated into the anchor strip as a lateralindentation which is simple to produce. By connecting the anchor stripand the steel component within the scope of the production, each recessis then completed to form a type of eye through which at least one steelbar of the steel bar mesh engages. An eye thus formed acts, as it were,as favored linkage point or favored force transmission interface betweenthe concrete component and the steel component.

In an expedient development, a plurality of regularly arranged recessesin the manner of a tooth row are provided. As a result, a very largenumber of favored linkage points and a uniform distribution thereof canbe achieved. Forces acting on the steel component are then alsotransmitted in a correspondingly uniform manner to the reinforcement andthus to the concrete component.

Preference is further given to an embodiment of the anchor strips inwhich each recess has the contour of a quadrangle or of a symmetricaltrapezium. These shapes promote, inter alia, a very simple and thuseconomically efficient production of the anchor strips.

Moreover, it is advantageous if the anchor strips used are profilestrips having an L-shaped cross section, T-shaped cross section, orI-shaped cross section. On the one hand, such a cross section produces abarb-like effect, that is to say an improved retention of an anchorstrip in the concrete, and, on the other hand, it is thus possible tohave recourse to commercially available standard profile articles forthe starting products for the production of the anchor strips. Moreover,I-profile strips, U-profile strips, double-T-profile strips andZ-profile strips as starting products are suitable for producing twoanchor strips in one production process. By means of a cut, extending inthe strip longitudinal direction, centrally through such a profile stripwith a cut pattern corresponding to a tooth row with quadrangular ortrapezoidal teeth, there will always result two identical anchor stripswith mutually complementary cut patterns which are offset with respectto one another in the strip longitudinal direction.

Since an anchoring system according to the invention is configured aboveall for ensuring the highest possible loading limits, the anchor stripsare preferably produced from steel, in particular from ferritic oraustenitic steel. In this context, it is accordingly considered to beadvantageous if each anchor strip is connected in an integrally bondedmanner, in particular welded, to the corresponding steel component.

By virtue of its load ability, an anchoring system according to theinvention is also suitable for the construction of a reactor safetycontainer, a pressure container or a tank container. According to atypical manner of construction, these are constructed from reinforcedand, if appropriate, prestressed concrete components which form theconcrete shell. Provided on the inner side of the concrete shell is asteel shell, also referred to as a liner, consisting of a number ofsteel components, which steel shell ensures that the concrete shell isleak tight. Finally, the steel components are connected non-releasablyto the concrete components with the aid of anchorages according to theinvention.

Precisely for the safety requirements of a reactor safety container(containment), the design and the construction of the anchorage of thesteel shell, also referred to as containment liner, of the reactorsafety container is of major importance. With respect to the permissiblestresses and rigidities, high requirements on the anchorage are definedin various standards and guidelines. The anchorage must withstand boththe forces and loads occurring in normal operation and also in the eventof a fault and at the same time prevent crack formation/crackpropagation in the steel shell. As has now been recognized, theserequirements can be met more efficiently if the steel shell, theanchorage and the reinforced concrete cooperate in the depth of theanchorage. In this regard, the anchoring system according to theinvention offers a maximum degree of effectiveness.

In order to understand this more clearly, the hitherto customaryanchoring systems will again be discussed briefly at this point:

The design and construction of previously used systems for anchoring thesteel shell are generally based on the use of standard L-profiles,T-profiles or Z-profiles which are cast in unmodified form directly intothe concrete and welded to the steel shell. These systems have thedisadvantages now described.

The anchoring profiles are usually welded directly to the steel shellusing continuous weld seams on both sides of the profile. Here, thewelding usually takes place manually. Here, in the case of a reactorcontainment, the lengths of all the weld seams add up to severalkilometers. Here, the manual welding work entails high costs.

The depth (profile height) of the anchoring profile is usually above 70mm and thus above the minimum of the required thickness of the concretecovering (=30-40 mm). The reinforcing layer can be placed only behind(below) the anchoring profiles. As a result, the maximum bendingcapacity of the reinforced concrete cross section is reduced.

The continuous anchoring profiles represent a physical barrier for theflow of the concrete during the casting process between the individualprofiles.

The anchoring profiles are embedded only in the applied layer of theconcrete without an interface to the reinforcement. As a result, theloading capacity of the anchorage with respect to normal and transverseshear stress is reduced to that of the embedded concrete. Results fromnumerous tests show that a failure of the concrete occurs before thefailure of the anchoring profiles.

The anchoring system proposed here, which can also be referred to as a“liner shaped anchorage system” provides a far better anchorage of thesteel shell (liner) by the specially shaped anchoring profiles (anchorstrips) which are provided with recesses for the reinforcement and whichallow a cooperation between the anchoring profiles and the reinforcedconcrete in the manner of a true composite structure. It balances theanchoring system and increases the efficiency of the anchorage. Itoffers, in particular, the advantages that are now listed.

By using the anchoring system according to the invention it is possibleto achieve a reduction of the required weld seam lengths by a factor of3 or more as a result of the regularly interrupted and thus shortenedconnecting surfaces without relevant weakening of the anchor strip-linerconnection. At the same time, a reduction in the previously requiredtime for preassembling a prefabricated part of the steel shell and alsoa reduction in the costs for welding work are achieved. These savingsconsiderably outweigh the outlay for cutting the starting profiles.

The anchoring system according to the invention allows parts of thereinforcement to be placed in the interspace between the continuousinner webs of the anchoring profiles and the steel shell connectedthereto at the outer connecting surfaces while taking the minimumrequired concrete covering into consideration. Moreover, the systemincreases the bending strength of the concrete cross section.

The recesses in the correspondingly shaped anchoring profiles preventthe formation of a continuous physical barrier which impedes the flow ofthe concrete during the casting process.

The anchoring profiles used couple/integrate at least two layers ofcrossed reinforcement. This increases the anchoring capacity and makesit possible to achieve a balance between the capacity of the profilesand the reinforced concrete.

The integration of the anchoring profiles in conjunction with thereinforcement affords a higher stability of the steel shell while theconcrete is being cast.

In summary, the anchoring system according to the invention withspecially shaped anchoring profiles offers an efficient solution forembedding the profiles into the concrete together with an optimizedinterface to the reinforcement and with simultaneously a large savingspotential with regard to the production costs and production times.Moreover, the use of this system increases the efficiency of theanchorage of the steel shell. It can be used both for reactor containersand other safety containers (containments) and gas and liquid containersand also for pressure containers.

The invention is described further by way of an exemplary embodiment.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin an anchoring system between a concrete component and a steelcomponent, it is nevertheless not intended to be limited to the detailsshown, since various modifications and structural changes may be madetherein without departing from the spirit of the invention and withinthe scope and range of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a diagrammatic, longitudinal sectional view, represented as adetail, of a structure, namely of a reactor containment, having ananchoring system according to the invention;

FIG. 2 is a cross-sectional view of two commercially available profilestrips; and

FIG. 3 is a side view of a U-profile strip with a cutting lineindicated.

DETAILED DESCRIPTION OF THE INVENTION

Parts which correspond to one another are provided with the samereference signs in all of the figures.

Referring now to the figures of the drawing in detail and first,particularly, to FIG. 1 thereof, there is shown the functional principleof an anchoring system according to the invention. A longitudinalsection, represented as a detail therein, shows a concrete component 1which, with the aid of at least one anchor strip 2, is non-releasableconnected to a steel component 3, also referred to as a liner plate,embodied in the manner of a flat steel plate. A plurality of anchorstrips 2 of this type can be situated at a certain distance behind oneanother perpendicularly to the drawing plane, although this cannot beseen from the figure.

Provided as the anchor strip 2 in this exemplary embodiment is a half ofa steel profile strip which can be produced by dividing into two acommercially available standard profile 4, 5 shown in FIG. 2 and FIG. 3.Here, the corresponding standard profile 4, 5 is severed along a cuttingline 7 extending substantially in the strip longitudinal direction 6.The cutting line 7 is preferably selected such that, as a consequence,there is formed, along both halves, a type of tooth row having teethseparated from one another by recesses or interspaces. By way ofexample, the shape of a symmetrical trapezium was selected both for theteeth and for the teeth interspaces of the tooth row. As a result, it ispossible to produce two usable anchor strips 2 with only one work step.Both anchor strips 2 can be considered as equivalent. They differ onlythrough an offset of the tooth row in the strip longitudinal direction6. To separate the standard profiles 4, 5, any suitable separatingprocess can be used, such as, for example, cutting, shearing, punchingand related processes such as, for instance, laser cutting.

Owing to the use of standard profiles 4, 5 in the production, eachanchor strip 2 has a strip-like retaining foot 8 which is formed fromthe corresponding upper or lower flange of the standard profile andwhich preferably projects outwardly from the plane of the teeth andrecesses, i.e. perpendicular to the drawing plane, which retaining foot,in the final mounting state of the anchoring system, also lies in theconcrete component 1 and therefore acts, as it were, as a barb. Toincrease the stability and distortion rigidity of the anchor strip 2,the recesses in the transverse direction 11 are not led completely asfar as the retaining foot 8, but there remains in each case a narrow web13 connected to the retaining foot 8.

In addition to the retaining foot 8, most of the remaining anchor stripbody in the final mounting state is also encapsulated by the concrete ofthe concrete component 1 by spraying or casting. Only the outer ends ofthe tooth row teeth, that is to say tooth prangs 9, project from theconcrete component 1. In the anchoring system according to theinvention, the exposed tooth prangs 9 serve as segments of a connectingsurface. Within the scope of the production process, welding, solderingor adhesive bonding is used to form at the segments of the connectingsurface in each case an integrally bonded connection between the anchorstrip 2 and the steel component 3. For this purpose, weld seams arepreferably applied on both sides, at the butting edges of the anchorstrip 2 and the steel component 3. By virtue of the recesses between theteeth, the total length of the connecting surface 9 in the longitudinaldirection 6 is only around ⅓ of the total length of the anchor strip 2.

A mesh consisting of steel bars 10 as a reinforcement is incorporatedinto the concrete component 1 of the exemplary embodiment. The meshcontains a plurality of layers which are stacked above one another in analternating sequence ABAB in the transverse direction 11. In FIG. 1,exactly four layers are represented. A different, in particular larger,number of layers can likewise be advantageous, however. The steel bars10 assigned to a layer A are arranged parallel to one another andparallel to the longitudinal direction 6 of the anchor strip 2 andperpendicular to the steel bars 10 of a layer B, which extendperpendicular to the drawing plane. As a result, the observer can see achecker board pattern in the transverse direction 11 when viewing thereinforcement from above, to the extent that this can be seen freelycorresponding to an exploded view. The steel bars 10 are preferablyconnected to one another at the contact points of the steel bars 10 oftwo layers situated directly above one another. Here, the type ofconnection can vary depending on the application. Particularly expedientvariants are adhesive bonding, welding or a wrapping with wire. Thesteel bars 10 of two layers AB situated directly above one another and,if appropriate, also further layers can also be interwoven in that, forexample, the steel bars 10 extending perpendicular to the drawing planeare guided past, alternately above and below, the steel bars 10 directlyadjacent to them and extending in the longitudinal direction 6.

Important to the anchoring system according to the invention is theincorporation of the anchoring element, in this case the anchor strip 2,into the steel bar mesh serving as reinforcement for the concretecomponent 1 in such a way that the action of forces on the steelcomponent 3 is transmitted via the anchoring element to thereinforcement. Acting forces thus act less locally and can accordinglybe better absorbed by the concrete component. By connecting the anchorstrip 2 and the steel component 3 within the scope of the production,each tooth interspace of an anchor strip 2 is formed in the manner of aneye 12. In each case a steel bar 10 of the steel bar mesh traverses suchan eye 12, with the result that transmission of force according to theobjective is possible at this point. Preferably, the steel bars 10traversing the tooth interspaces each bear against the inner web 13 ofthe anchor strip 2. Each tooth interspace can also be traversed by morethan one steel bar 10, or as an exception, by none, if at least someinterspaces of the anchor strip 2 are correspondingly traversed by thesteel bars 10. If, for example, tensile forces in the transversedirection 11 act on the respective anchor strip 2, the latter is securednot only via its retaining foot 8 in the concrete but is additionallyanchored by the upper two layers of the steel bar mesh.

In the exemplary embodiment according to FIG. 1, the steel bar mesh hasfour layers of crossed and, if appropriate, partially interwoven steelbars 10, wherein the steel bars 10 of the lowermost layer, as seen inthe direction of insertion into the concrete component 1, areperpendicular to the drawing plane and are guided past below theretaining foot 8 of the anchor strip 2, parallel to the steel bars 10traversing the tooth interspaces further above. Some of the steel bars10 of the immediately higher layer which extend longitudinally withrespect to the anchor strip 2 can in this case be arranged in such a waythat they are supported from above on the retaining foot 8 and thus donot directly come into contact with the steel bars 10 of the lowermostlayer which extend perpendicular thereto.

1. A reinforced concrete-steel structure, comprising: a concretecomponent; a reinforcement having at least one steel bar mesh with steelbars; a steel component connected non-releasable to said concretecomponent; and at least one anchor strip having a connecting surface forconnecting to said steel component and defining a connection betweensaid steel component and said concrete component, said anchor stripbeing cast into said concrete component such that said connectingsurface of said anchor strip projecting from said concrete component,said anchor strip having a number of recesses formed therein andextending at least partially into said concrete component and each beingtraversed by at least one of said steel bars of said steel bar mesh,each of said recesses being an indentation open toward said steelcomponent and separating said connecting surface of said anchor stripinto subregions spatially separated from one another.
 2. The reinforcedconcrete-steel structure according to claim 1, wherein a regularconfiguration of said recesses in a manner of a tooth row is provided insaid anchor strip.
 3. The reinforced concrete-steel structure accordingto claim 1, wherein said recesses each have a quadrangular contour. 4.The reinforced concrete-steel structure according to claim 1, whereinsaid recesses each have a contour of a symmetrical trapezium.
 5. Thereinforced concrete-steel structure according to claim 1, wherein saidanchor strip is cut from a profile strip having an L-shaped crosssection, a T-shaped cross section, a double-T-shaped cross section, anI-shaped cross section, a U-shaped cross section or a Z-shaped crosssection.
 6. The reinforced concrete-steel structure according to claim1, wherein said anchor strip is formed from steel.
 7. The reinforcedconcrete-steel structure according to claim 1, wherein said anchor stripis connected in an integrally bonded manner at said connecting surfaceto said steel component.
 8. The reinforced concrete-steel structureaccording to claim 1, wherein said anchor strip is one of a plurality ofanchor strips disposed next to one another.
 9. The reinforcedconcrete-steel structure according to claim 1, wherein said steelcomponent is a steel plate.
 10. The reinforced concrete-steel structureaccording to claim 8, wherein said steel bar mesh has at least fourlayers of crossed said steel bars, wherein said steel bars of alowermost layer of said steel bar mesh, as seen in a direction ofinsertion into said concrete component are guided past below said anchorstrips.
 11. The reinforced concrete-steel structure according to claim1, wherein the reinforced concrete-steel structure is selected from thegroup consisting of a reactor safety container, a pressure container anda gas and liquid tank.
 12. The reinforced concrete-steel structureaccording to claim 1, wherein said anchor strip is formed from ferriticsteel or austenitic steel.
 13. The reinforced concrete-steel structureaccording to claim 1, wherein said anchor strip is welded at saidconnecting surface to said steel component.
 14. The reinforcedconcrete-steel structure according to claim 8, wherein said anchorstrips are oriented parallel to one another.
 15. The reinforcedconcrete-steel structure according to claim 8, wherein said steel barmesh has at least four layers of crossed and partially interwoven saidsteel bars, wherein said steel bars of a lowermost layer of said steelbars, as seen in a direction of insertion into said concrete componentare guided past below said anchor strips.